One of the enduring mysteries of the Benghazi massacre is the lack of any serious attempt to render assistance to those trapped in the consulate and the CIA annex building. We know the resources were available at Sigonella Naval Air Station in Sicily, one to two hours away by air. We know that Special Forces units were moved from Central Europe to Italy in anticipation of a “go” order. So why didn’t they go?

At PJ Media, former Navy SEAL Matt Bracken explains that the authority to cross a national border on a hostile mission, such as a rescue in Benghazi, can only come from the President. Not the Vice President, not the Secretary of Defense, not the Joint Chiefs of Staff, not even from regional commanders in the area. They can preposition all they want, but, in the end, the only person with “cross-border authority” is, for now, Barack Obama:

The Benghazi debacle boils down to a single key factor — the granting or withholding of “cross-border authority.” This opinion is informed by my experience as a Navy SEAL officer who took a NavSpecWar Detachment to Beirut.

Once the alarm is sent – in this case, from the consulate in Benghazi — dozens of HQs are notified and are in the planning loop in real time, including AFRICOM and EURCOM, both located in Germany. Without waiting for specific orders from Washington, they begin planning and executing rescue operations, including moving personnel, ships, and aircraft forward toward the location of the crisis. However, there is one thing they can’t do without explicit orders from the president: cross an international border on a hostile mission.

That is the clear “red line” in this type of a crisis situation.

No administration wants to stumble into a war because a jet jockey in hot pursuit (or a mixed-up SEAL squad in a rubber boat) strays into hostile territory. Because of this, only the president can give the order for our military to cross a nation’s border without that nation’s permission. For the Osama bin Laden mission, President Obama granted CBA for our forces to enter Pakistani airspace.

On the other side of the CBA coin: in order to prevent a military rescue in Benghazi, all the POTUS has to do is not grant cross-border authority. If he does not, the entire rescue mission (already in progress) must stop in its tracks.

Ships can loiter on station, but airplanes fall out of the sky, so they must be redirected to an air base (Sigonella, in Sicily) to await the POTUS decision on granting CBA. If the decision to grant CBA never comes, the besieged diplomatic outpost in Benghazi can rely only on assets already “in country” in Libya — such as the Tripoli quick reaction force and the Predator drones. These assets can be put into action on the independent authority of the acting ambassador or CIA station chief in Tripoli. They are already “in country,” so CBA rules do not apply to them.

How might this process have played out in the White House?

Read the rest to see Mr. Bracken’s speculations regarding what happened that night in the White House. It’s an enlightening piece from someone who knows how these situations operate.

It also sheds light on another mystery. It’s been reported that one of the former SEALs defending the Annex had put a targeting laser on a jihadi mortar crew, something he would do only if he expected help and was trying to direct incoming fire. This lead to speculation that there was an AC-130 gunship over Benghazi at time time, but that it was denied permission to fire. If Mr. Bracken’s analysis is correct, it’s quite possible a craft was launched from Sicily with the expectation that CBA would be coming soon. Did the SEAL trapped in Benghazi know that the gunship was close, and was painting the target to be ready for it?

We may never know.

But what we do know, thanks to Mr. Bracken, is that sole responsibility for the American response that night lies with President Barack Obama. Whether by actively denying permission or passively not making a decision (by going to bed?), President Obama left those men to die.